A security source said on Monday that "eleven terrorist elements were killed in an exchange of fire" with security forces in el-Arish, the capital of North Sinai province.
The militants were in an abandoned petrol station "preparing terrorist acts" against security forces, the source added, Presstv Reported.
According to official figures, around 300 suspected militants and at least 35 soldiers have been killed since the February launch of the "Sinai 2018" operation.
The army launched the campaign on February 9 after President Abdel Fattah el-Sisi gave it a three-month deadline to crush the Daesh Takfiri terrorist group in Sinai.
Sisi has said setbacks by Daesh in Syria were driving its terrorists to try to relocate to Libya and Sinai. The group has killed hundreds of soldiers, policemen and civilians, mainly in its North Sinai stronghold but also elsewhere in Egypt.
The Sinai Peninsula has been under a state of emergency since October 2014, after a deadly terrorist attack left 33 Egyptian soldiers dead.
Over the past few years, terrorists have been carrying out anti-government activities and fatal attacks, taking advantage of the turmoil in Egypt that erupted after the country’s first democratically-elected president, Mohamed Morsi, was ousted in a military coup in July 2013.
The Velayat Sinai group, which is affiliated with Daesh, has claimed responsibility for most of the assaults. The group has expanded its attacks to target members of Egypt’s Coptic Christian community as well as foreigners visiting the country, prompting Cairo to widen its controversial crackdown, which critics say has mostly targeted dissidents.